Ordered arrays of magnetic nanowires investigated by polarized small-angle neutron scattering

Polarized small-angle neutron scattering (PSANS) experimental results obtained on arrays of ferromagnetic Co nanowires ($\phi\approx13$ nm) embedded in self-organized alumina (Al$_{2}$O$_{3}$) porous matrices are reported. The triangular array of aligned nanowires is investigated as a function of the external magnetic field with a view to determine experimentally the real space magnetization $\vec{M}(\vec{r})$ distribution inside the material during the magnetic hysteresis cycle. The observation of field-dependentSANSintensities allows us to characterize the influence of magnetostatic fields. The PSANS experimental data are compared to magnetostatic simulations. These results evidence that PSANS is a technique able to address real-space magnetization distributions in nanostructured magnetic systems. We show that beyond structural information (shape of the objects, two-dimensional organization) already accessible with nonpolarized SANS, using polarized neutrons as the incident beam provides information on the magnetic form factor and stray fields \textgreek{m}0Hd distribution in between nanowires.